Control circuitry may be configured to control a switch to deliver electrical power to an electrical load. The control circuitry may employ pulse-width modulation (PWM), phase-shift modulation, and/or pulse-frequency modulation (PFM) to control the electrical power that the switch delivers to the electrical load. For PWM, the control circuitry may vary the duty cycle, and for PFM, the control circuitry may vary the frequency. The control circuitry may be configured to determine the duty cycle, phase shift, and/or frequency based on information that the control circuitry receives from the switch, the power supply, or the electrical load.